With her death, Monsegur’s life tilted on its axis. At 26, he became head of a household, taking over as parent to his aunt’s two children, both under 7 at the time. It wasn’t a job he wanted. “I took up the responsibility out of consequence,” he wrote in one chat log. “My family is small. I did not want the girls to go through the system.” If he didn’t take them, the city might. One neighbor told me, “He sacrificed his life for those girls.”

Still, Monsegur was a proud parent, even if the job overwhelmed him. “Being a parent ain’t easy,” he wrote to an online friend. “… So much shit going on at the same fucking time.”

And with the two girls to support, Monsegur’s tenuous financial condition became a crisis. He’d been living on unemployment benefits of $400 a week. By December 2010, six months after his grandmother’s death, and the disappearance of her Social Security check, he was desperate. “He was angry and frustrated about losing his job,” said a person who talked to him at the time. “That’s what threw him into the hacker scene.” Monsegur began to lead a double life. In the physical world, he wanted to be a responsible parent, even if he dabbled in crime, trying to move a pound of marijuana in that period. But his online persona was increasingly out of control. He didn’t seem to recognize limits or laws. In December, 2010, Sabu went on a crime spree. “I only hack for profit now … gotta make that money,” he wrote to Kelly Hallissey, an ­online interlocutor, that month.

On December 6, he sent a message from his Facebook account: “Yo papi I just got a corporate account that has at least 400k in it,” then supplied apparent account information, presumably so the account could be looted. On December 13, he sent the same person the credit-card and Social Security numbers for a couple of dozen people. He claimed to have gotten some information by downloading PDFs of TurboTax returns via Google. He obtained stolen credit-card numbers. “I used these [cards] … to pay my own bills,” he later admitted. He got ahold of a former employer’s credit-card information, and hacked into an auto-parts company’s computer system and had four engines worth $3,450 shipped to him. Monsegur turned himself into a kind of comic-book supercriminal. “You clearly don’t know anything about me,” he wrote to a friend in late December 2010. “How about you ask who sabu is first before you talk shit before you get owned into next year.”

But crime-for-profit quickly became a sideline to Monsegur’s real business on the web, which was attacking powerful institutions. Monsegur later said that Anonymous was the movement he’d been waiting for all his life. “It lives, it thinks, it breathes,” he said. “We give police officers in the United States the power to shoot us and get away with it. Anonymous can now stand up to that threat.”

As a movement, Anonymous had its roots in the online adolescent playpen 4chan, and many hackers joined up for the “lulz,” which included goofy and inconsequential schoolboy pranks, like having pizzas sent to a target’s home. Some Anonymous hackers wanted to do little more than sow mayhem—to “fuck shit up,” as one explained. Or, to use a favorite word, perpetrate “motherfuckery.” Sabu distinguished himself by being deadly serious. His rhetoric, redolent of the most radical of sixties activists, thrilled and inspired his online comrades. “He played the principled warrior,” said Samantha Murphy, a journalist who followed the chat rooms. “He gave them a reason to be angry and made it into a real rebellion.” And he embraced his roots. Once he had hoped to trade a life in the projects for a career. Now he was “talking shit and angry at society,” like the people he’d grown up with. “My nigga” and “my brother,” he called fellow hackers, most of them young white kids. Anonymous was said to be leaderless, but strong personalities dominated, and Sabu’s was one. He issued commands: “Use your skills to disrupt the governments communications for the cause,” he tweeted. He scoped out targets, mentioning one law firm. “I see some potential openings … we could rape these niggers,” he wrote. He bullied people into line and at the suggestion of insubordination meted out discipline. “I’m about to start owning nigg3rs,” he wrote.

Sabu’s online fame grew along with Anonymous’s notoriety, and his anger helped shape Anonymous’s identity. He sympathized with the marginalized. And if the lulz were a driving force, Sabu helped make fighting oppression another. By January 2011, the Middle East was erupting—in part owing to WikiLeaks’ revelations. From his apartment in the projects, Sabu took control of a local Tunisian’s computer and, as he’d done after Vieques, defaced the website of Tunisia’s president—he posted an Anonymous logo. For Sabu, it was a peak experience. “You don’t know the feeling of using this guy’s Internet to hack the president’s website,” he later told Parmy Olson, author of the just-published We Are Anonymous, a remarkable inside account of the hacker movement. “It was fucking amazing.”